Rugose Coral (Horn Coral)
Order Rugosa (solitary rugose coral, cf. Heliophyllum or similar genus) • Body fossil, invertebrate
Geological Period
Devonian
Estimated Age
350 to 400 million years old
Preservation Type
Permineralization and heavy replacement by silicates or calcite, maintaining external shape and internal coral structures.
Condition Assessment
Good condition. The specimen is largely complete with clear structural features visible, though displaying surface weathering and iron staining.
Taxonomic Classification
Phylum: Cnidaria, Class: Anthozoa, Order: Rugosa
Morphological Description
Elongated, horn-shaped corallite structure tapering toward a pointed base with a visible circular calice (cup) at the wider end showing internal septal structures radiating inward.
Rock Matrix
Weathered limestone and sandstone matrix with iron oxide staining (limonite/goethite) giving a brownish-tan coloration.
Formation & Location
Found globally in ancient marine limestone formations, commonly in the Midwestern United States (e.g., Jeffersonville Limestone) or European Devonian deposits.
Size & Dimensions
Approximately 8 cm to 10 cm in length, typical for a medium-sized solitary rugose coral.
Value & Rarity
Estimated Market Value
$15 to $40
Auction Estimate
$10 to $30
Rarity Assessment
Common
Scientific Significance
Important for paleoenvironmental reconstructions, indicating shallow, warm, tropical marine environments during the Paleozoic era.
Preparation Recommendations
Gentle mechanical cleaning with a soft brush to remove loose matrix. Store in a dry environment to prevent further weathering.
Notable Features
Distinct horn-like curvature with a well-defined circular calice showcasing radial septal patterns.